1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a semiconductor device having a nitride-based semiconductor field effect transistor structure and a method of manufacturing the same.
2. Description of the Related Art
In general, a group III-nitride-based semiconductor including group III elements such as gallium (Ga), aluminum (Al), indium (In), or the like, and nitrogen (N), has characteristics such as a wide energy band gap, high electron mobility, high saturation electron speed, high thermochemical stability, and the like.
A nitride-based field effect transistor (N-FET) based on the group III-nitride-based semiconductor is manufactured using a semiconductor material having a wide energy band gap, for example, gallium nitride (GaN), aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), aluminum indium gallium nitride (AlINGaN), or the like.
A semiconductor device having a general N-FET includes a base substrate, a nitride-based semiconductor layer formed on the base substrate, and a source electrode and a drain electrode formed on the semiconductor layer, and a gate electrode formed on the semiconductor layer between the source electrode and the drain electrode.
However, a field effect transistor using gallium nitride (GaN) is continually in a ‘turned-on’ state in which current flows due to low resistance between a drain electrode and a source electrode when gate voltage is 0V (normal state), such that it consumes current and power. For turning-off the field effect transistor, there is a disadvantage in that negative voltage should be applied to a gate electrode (normally-on structure).